Although the black coffee has expired and has not been opened, it may have gone bad. For example, black coffee is moldy, but the color of black coffee is dark and difficult to distinguish. The taste of black coffee changes obviously after expiration, and pathogenic microorganisms exist, which is easy to cause physical discomfort.

Moreover, even black coffee within the shelf life may deteriorate due to packaging or storage problems, while black coffee beyond the shelf life is even more insecure in quality, and it is generally not recommended to continue eating.

Characteristics of black coffee

Black coffee is much lower in calories than other coffees, so it is also a must-have drink for friends who are losing weight. The first characteristic of black coffee is bitterness, because it does not add any seasoning, so it shows the most mellow coffee taste. The intensity of bitterness is closely related to the origin, roasting degree and brewing method of coffee beans.

Another feature of black coffee that has to be mentioned is sweetness. Of course, the sweetness of black coffee is very different from that after adding sugar or milk. The sweetness of black coffee is mostly manifested in the late stage of tasting, which is also called back sweetness. The sweetness of coffee has a lot to do with brewing. The first stage is to extract the sour taste of coffee, and the second stage is to extract the aroma of coffee.